【摘要】 钻形紫菀为小麦与白菜的常见农田杂草;为探究其入侵机理,采用培养皿法研究了钻形紫菀茎、叶水浸提液对小麦与白菜萌发和生长的影响。结果表明:1)小麦和白菜的萌发率、萌发指数随水浸提液浓度增加而降低,且小麦萌发对低浓度钻形紫菀水浸提液不敏感,但在高浓度水浸提液处理下(20,40g·L-1)受到的抑制较白菜强。2)水浸提液对小麦和白菜的鲜重、苗长和根长具有抑制作用,且随浓度的增加抑制作用增强。其中,水浸提液对白菜的鲜重、苗长仅在较高浓度(20,40g·L-1)时具有显著抑制作用,而对小麦的鲜重、苗长的抑制在低浓度(5,10g·L-1)时即达到显著性水平,且在各浓度下均比白菜强;白菜根长在5g·L-1水浸提液处理下抑制效应不显著,而在其他浓度下受到的抑制较小麦强。3)随水浸提液浓度增加,除白菜过氧化氢酶(CAT)活性呈波动趋势外,其余保护酶[CAT、过氧化物酶(POD)、超氧化物歧化酶(SOD)]活性均逐渐降低,膜透率以及白菜丙二醛含量均逐渐上升,小麦丙二醛含量则呈先降后升的趋势,根系活力与叶绿素含量均呈下降趋势;总体而言,白菜生理指标受到的抑制更强。研究表明,钻形紫菀水浸提液可通过降低保护酶活性、破坏膜系统以及影响呼吸作用和光合作用来抑制2种植物的萌发和生长。4)各浓度下白菜化感综合效应的绝对值均大于小麦,说明白菜对钻形紫菀水浸提液更为敏感。更多还原

【Abstract】 Aster subulatus is a common weed of wheat（Triticum aestivum） and Chinese cabbage（Brassica chinensis） in farmland. To explore its invasion mechanism, a Petri dish method was used to evaluate the potential allelopathic effect of aqueous extracts from the stem and leaf of A. subulatus on T. aestivum and B. chinensis. In general, the germination rates and germination indexes of T. aestivum and B. chinensis decreased with increasing concentrations of the A. subulatus aqueous extracts. T. aestivum was not sensitive to lower concentrations of the aqueous extracts but was more strongly inhibited than B. chinensis by higher concentrations(20, 40 g·L^-1) of the aqueous extracts. The fresh weight, shoot length, and root length of T. aestivum and B. chinensis were more strongly inhibited as the concentration of the aqueous extracts increased. The aqueous extracts at higher concentrations(20, 40 g·L^-1) had significant negative effects on the fresh weight and shoot length of B. chinensis, and significant negative effects on those of T. aestivum at lower concentrations(5, 10 g·L^-1). In all treatments, higher concentrations of the aqueous extracts had stronger negative effects than lower concentrations. The aqueous extracts at the lowest concentration(5 g·L^-1) negatively affected the root length of T. aestivum, but not that of B. chinensis. As the concentration of the aqueous extracts increased, the activities of protective enzymes（catalase, peroxidase, superoxide dismutase） gradually decreased, except that the catalase activity fluctuated in B. chinensis. During treatment with the aqueous extracts, the malondialdehyde content and membrane permeability gradually increased in B. chinensis, while the malondialdehyde content of T. aestivum decreased first and then increased, and its root activity and chlorophyll content showed downward trends. Overall, the aqueous extracts had stronger negative effects on the physiological indexes of B. chinensis than on those of T. aestivum. The results of this study showed that aqueous extracts of A. subulatus inhibited the germination and growth of two crop plants by reducing protective enzyme activities, disrupting the membrane system, and affecting respiration and photosynthesis. For all measured indexes, the standard error values were higher for B. chinensis than for T. aestivum, indicating that B. chinensis was more sensitive than T. aestivum to the aqueous extracts of A. subulatus.更多还原